High speed DSL systems such as VDSL systems require the DSL connection (i.e. the part of the connection over copper cables) to be as short as possible in order to provide the fastest connections. It has therefore been proposed to place DSL modems at the network side (network modems) at so called “drop points”. Such drop points might typically, for example, be at the top of a telegraph pole from where a number of telephone lines fan out each heading towards a different house. Such a point is likely to be the final distribution point before the external cable reaches the customer's premises.
In such situations it can be difficult for the network modem at the distribution point to obtain a reliable power supply from its immediate vicinity. Solutions have therefore been devised by which power is supplied from the consumer's premises over the copper pair connection together with the DSL signals.
In such scenarios normal telephony is normally provided by a Voice Over Internet Protocol (VOIP) solution. Generally, to provide this VOIP solution, the DSL modem in the customer's premises is configured to provide a socket (or jack) into which a conventional lead, having a conventional plug (e.g. a Registered Jack (RJ) 11 or 45 plug or a conventional BT plug (BS6312 431A plug), etc.) from a conventional telephone apparatus may be plugged. The modem (by means of a module referred to as an Analog Telephone Adapter (ATA)) simulates all of the Plain Old Telephone System (POTS) functionality generally provided by a conventional master socket which provides the interface between the customer's premises and the access network such that the telephone (for example an analog telephone) can operate normally as though it were directly connected to the master socket (e.g. a conventional British Telecommunications (BT) Network Termination Equipment (NTE) 5 model) or an extension socket correctly connected to the master socket.
However, when a telephone is connected directly to the user modem in this way, it becomes difficult for a user to use any existing extension telephone wiring (e.g. to extension sockets) for connecting additional telephones in locations which may be considerably removed from the user's modem.
Co-pending European patent application No. EP10251572.3 filed on 10 Sep. 2010 describes a solution to this problem which requires at least three wires to be present in the user's extension wiring.